Subtypes of postpartum depressive symptoms and the association with subsequent psychiatric care: latent class analysis

BACKGROUND: Postpartum depressive symptoms can vary substantially and probably reflect distinct subtypes. Understanding specific symptom patterns may help identify those at risk for later psychiatric care. AIMS: We aimed to identify subtypes of postpartum depressive symptoms and examine their associations with subsequent psychiatric care. METHOD: We conducted a cohort study using Danish nationwide health registers linked to population-based Edinburgh Postnatal Depression Scale (EPDS) scores from 2015 to 2021. Latent class analysis of EPDS responses identified subtypes among women with clinically relevant symptoms (EPDS ≥11), using a maternal background population as a reference group (EPDS <11). The outcome was psychiatric hospital contacts or redeemed psychotropic prescriptions within 1 year postpartum. We estimated standardised cumulative incidence rates and risk ratios using spline-based, time-to-event models. RESULTS: Among 162 079 women, 11 847 (7.3%) had clinically relevant symptoms (EPDS ≥11). Five subtypes were identified: Mild-depressive (23%), Moderate-anxious (17%), Moderate-depressive (18%), Moderate-overwhelmed (31%) and Severe-depressive (11%). At 1 year, the standardised cumulative incidence of psychiatric care was 69.6 (95% CI, 61.4-79.0) per 1000 persons in the Mild-depressive subtype. Compared with this group, the adjusted risk ratio was 0.33 (95% CI, 0.28-0.38) in the background maternal population, between 1.11 (95% CI, 0.93-1.32) and 1.25 (95% CI, 1.06-1.48) across moderate subtypes and 2.37 (95% CI, 1.99-2.82) for the Severe-depressive subtype. CONCLUSIONS: Distinct subtypes of postpartum depressive symptoms were associated with varying risks of subsequent psychiatric care, depending on both symptom severity and symptom type. These findings underscore the importance of systematic screening and tailored follow-up, even for women with mild to moderate symptoms.